1. Field of the Invention
The present invention relates generally to semiconductor integrated circuits, and more particularly, to a spherical shaped semiconductor integrated circuit and the use of TIR holography in a system and method for use in manufacturing the same.
2. Discussion of the Related Art
Total internal reflection (TIR) holograms are constructed from expanded laser beams, as is known in the art. Referring now to FIG. 1, consider for example, a holographic recording layer 10 is disposed on a transparent flat substrate 12. Substrate 12 is in optical contact with a large right angle prism 14. With the use of expanded laser beams 16, 18 as shown in FIG. 1, TIR holograms can be constructed. One beam, referred to as the object beam 16, is directed through a mask transparency 20 to the holographic recording layer 10. The other beam, referred to as the reference beam 18, is directed through another face of the prism 14 so that it is totally reflected from the internal surface 22 of the holographic recording layer 10. The optical interference of the two beams 16, 18 is recorded by the holographic recording layer's photosensitive material. Subsequent to exposure, the holographic recording layer 10 is developed and fixed according to the particular processing steps required for the holographic recording layer. Once developed and fixed, the hologram stored in the holographic recording layer 10 can be reconstructed by irradiating it with a laser beam directed in the opposite direction to the original reference beam 18.
U.S. Pat. No. 5,640,257 discloses an apparatus and method for the manufacture of high uniformity 2-dimensional total-internal-reflection (TIR) holograms. In the '257 patent, the manufacture of TIR holograms includes the division of an input laser beam into an object beam and a reference beam. The direction of the beams to a holographic recording layer is adjusted a) so that the object beam is incident on a surface of the holographic recording layer following transmission through an object mask and b) so that the reference beam is incident on the other surface of the holographic recording layer. The reference beam is directed at an angle such that following passage through the holographic recording layer, the reference beam is totally internally reflected back into the holographic recording layer. The object beam and the reference beam are superposed at the holographic recording layer. Displacement of the input beam causes the object and reference beams to traverse together along the holographic recording layer. The '257 method and apparatus, however, is only applicable for 2-dimensional, flat lithography.
Hologram formation is sensitive to mechanical and other instabilities. A hologram is a recording of an optical interference pattern. A hologram will only be formed successfully if at each point on the recording surface the relative phases of the interfering object and reference beams are substantially constant during the exposure process.